COC use, ACE/AGT gene polymorphisms, and risk of stroke

To clarify the effects of the association between combined oral contraceptives (COC) use and ACE/AGT gene on stroke risk, and to undertake a preliminarily study of the molecular mechanism of the association between COC exposure and predisposing genes of hypertension on the increased risk of stroke.

This study was a multi-center case-control study based on the population of 25 towns in the surveillance regions of Jiangsu province, China.

(i) The univariate analysis of the frequency of the DD genotype of ACE insert/delete (I/D) polymorphism between the cases and controls indicated its significant association with the stroke (P<0.01), especially for hemorrhagic stroke (P<0.01). (ii) Women with COC exposure and ACE I/D genotype had an increased risk for all strokes [adjusted odds ratio 5.63; 95% confidence interval (CI), 2.20, 15.68], and an increased risk for hemorrhagic stroke (adjusted odds ratio 31.53; 95% CI, 3.54, 281.14) after adjustment for education and occupation. (iii) Multivariate analyses showed that hypertension was the most important risk factor for hemorrhagic stroke and ischemic stroke. COC use was a significant risk factor for hemorrhagic stroke. The combined effects of COC use, for 15 years and above, and ACE I/D polymorphism increased the risk of all strokes by more than eight times, and the risk of hemorrhagic stroke by more than 15 times.

Hypertension was a most important risk factor for stroke incidence. The D allele of ACE I/D polymorphism may be a potential risk allele for stroke. COC users carried the ID+DD genotype that may further increase the risk of stroke, especially for hemorrhagic stroke.